已知sinθ+sin∧2(θ)=1,求3cos∧2(θ)+cos∧4(θ)-2sinθ_数学解答

已知sinθ+sin∧2(θ)=1,求3cos∧2(θ)+cos∧4(θ)-2sinθ

人气：454 ℃　时间：2020-03-25 03:26:30

解答

sinθ+sin^2θ=1
sinθ=1-sin^2θ=cos^2θ
3cos^2θ+cos^4θ-2sinθ
=3sinθ+sin^2θ-2sinθ
=sin^2θ+sinθ
=1